Nutating disc vibrator

ABSTRACT

A nutating disc vibrator includes a nutating disc mounted within a cavity in a casing and guided by cooperating surfaces of the cavity. An inlet for a working fluid directs the working fluid along a path substantially in the plane of symmetry of the nutating movement and the working fluid itself is conducted only through stationary parts of the casing.

United States Patent 1191 -Giirtner Mar. 12, 1974 NUTATING DISC VIBRATOR2,960,316 11/1960 McKellar 259/1 R 1 1 Friedrichstrasse 21, $52233?311353 51122511111111; ..'.1"..i ."5'/13 7501 Bruchhausen, Germany [22]Filed: 1972 Primary Examiner-R0bert W. Jenkins [21] App]. No: 288,291Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [30] ForeignApplication Priority Data 7 A CT July 20. I972 Germany 2235585 [57]BSTRA A nutating disc vibrator includes a nutating disc 512] 259/1 R,227D]? 43 mounted within a cavity in a Casing and guided by operatingsurfaces of the cavity. An inlet for a working 1 0 can l1 8 8 fluiddirects the working fluid along a path substan- 7 tially in the plane ofsymmetry of the nutating movement and the working fluid itself isconducted only [56] References cued through stationary parts of thecasing.

UNITED STATES PATENTS 2,778,612 1/1957 Peterson 259/] R 19 Claims, 8Drawing Figures Mex. \r 1 NUTATING DISC VIBRATOR This invention relatesto a vibrator including a cavity and a nutating disc within the cavitydriven by a working fluid and guided by cooperating surfaces within thecavity.

Many forms of vibrators for compacting pourable mouldable masses such asconcrete prior to hardening are known.

In pneumatic vibrators an inertial element is moved by compressed air tocause the vibration. These known vibrators, however, have required valvemeans for controlling the compressed air and the valve means 'is notonly liable to be troublesome but tends to be expensive.

Also known are nutating disc motors but these also have required valvemeans to control the entry and exit of the working fluid, the valvemeans being contained partly within bearing means for the disc itself.

It is an object of the present invention to provide a vibratorcomprising an inertial element which can be driven by a working fluidwithin a cavity in a casing and wherein no valve means is required tocontrol the entry and exit of the working fluid to and from thevibrator.

To this end, the present invention provides a vibrator comprising acasing, a cavity within the casing, nutating inertia discmeans in thecavity guided by cooperating surfaces of the cavity, and inlet means andoutlet means for conducting a working fluid into and out from the cavitywherein said inlet means is positioned in a wall of the casing to directthe working fluid into the cavity along a path lying substantially inthe plane of symmetry of the nutating movement of said disc meanswhereby working fluid directed into the casing by the inlet means willimpinge upon the disc means to cause nutating movement thereof,the inletmeans and the outlet means further being arranged to conduct the workingfluid exclusively through stationary parts of said casing.

The location of the inlet means assists in starting the vibrator and thefact that the working fluid is conducted only through the stationaryparts of the casing promotes trouble free operation. Conveniently theworking fluid is a compressed gas such as nitrogen bu't compressed airis also satisfactory.

The dimensions of the vibrator may vary depending upon the particularapplication for the vibrator. Furthermore, the speed of nutation of thedisc and hence the frequency of vibration can be steplessly variedwithin a wide range by changing the pressure and consequently the flowrate of the working fluid, for example between and 500 cycles persecond. The pressure of a compressed air supply may be varied between0.5

tion of maximum inclination wherein its axially opposite faces makelinecontact each with a respective generator of a respective one of theconical portions. It is also preferred that supporting elements areprovided at the apices of the conical portions to ensure that the discwill be tilted when it comes to rest and this greatly facilitatesstarting.

In one preferred embodiment the two supporting elev ments are ball endedrods with the'balls thereof re ceived in sockets in axially oppositefaces of the disc and with the rod portions thereof received in conicalrecesses in the apices of the conical portions. This is a particularlygood arrangement for ready starting.

In an alternative embodiment the disc is mounted on a central ball whichis retained in sockets at the apices of the conical portions. Preferablythe central ball is movably received in a central opening in the discand in order to minimise friction the ball is less than one tenth of thediameter of the disc.

In another 'useful'embodiment of the vibrator the disc is carried onball bearing means or a cylindrical roller bearing on a central shaftcarried at its ends in the apices of the conical portions.

The outlet means may suitably comprise a plurality of channels connectedin parallel with the sum of their cross-sections selected in accordancewith the required cross-section of the outlet means. Such a subdivisioninto separate channels can eliminate the need to provide filter meansfor preventing the ingress of dirt.

Withadvantage the disc may have conical recesses in its axially oppositefaces in conformity with the conical portions of the cooperatingsurfaces or it may be a flat and I2 atmospheres. The proposed vibratoris particularly useful in association with shuttering and formwork inbuilding construction, though in suitably modified form it can also beused for purposes such as massage and the like. In one preferredembodiment the cooperating surfaces in the cavity are so shaped that theouter periphery of the disc is in rolling engagement therewith and thisarrangement is particularly suitable for trouble-free operation of thevibrator.

In order to enhance the running of the vibrator, at least one side ofthe disc may be supported by the easing. Preferably the cooperatingsurfaces include two mirror-symmetrical coaxial conical portionsprojecting inwardly of the cavity. The disc is then positioned betweenthe conical portions so that it can tilt to a posicircular disc.

To assist starting the vibrator, the periphery of the disc may bechamfered to a sharp edge, and preferably the chamfering will besymmetrical on both sides of the disc. It is also contemplated that achannel be provided in the casing wall adjacent the inlet means withinthe cavity, this channel being equal in length to about half thethickness of the disc. Such a channel extending parallel to thedirection of rotation of the disc will provide a satisfactorydistribution of working fluid within the cavity and will assist startingof the vibrator.

The casing of the vibrator may comprise two elements joined in theregion of the plane of symmetry of the nutating movement of the disc.Each element contains mirror-symmetrical concavities defining oneoverall cavity within the casing and a nozzle may be provided as theentry means for working fluid in the parting plane of the two elements.

The nozzle itself can with advantage be constructed so that thecross-section of its orifice increases with rising pressure of theworking fluid. Such an arrangement improves the efficiency of thevibrator by reducing the consumption of working fluid in the event ofthe vibration frequency being controlled by variations in the workingpressure. This end is achieved by providing a nozzle mouthpiece which iselastically deformable by the working fluid. The inlet orifice can thenbe expanded when the pressure of the working fluid rises and theadjusted cross-section will provide an approximately constant velocityof flow of the working fluid.

By way of example, the accompanying drawings illustrate certainpreferred embodiments of the invention. In the drawings:

FIG. 1 is a cross-sectional view of the vibrator taken on the line l-1of FIG. 2

FIG. 2 is a plan view of the vibrator shown in FIG. 1

FIG. 3 is a cross-sectional view of an alternative disc having nocentral bearing means;

FIG. 4 is a detail cross-sectional view of the disc shown in FIG. 1

FIG. 5 is a cross-sectional view of another alternative disc providedwith a central ball race bearing means FIG. 6 is a cross-sectional viewof yet another alternative disc provided with a central ball bearingmeans FIG. 7 is a detail cross-sectional view showing the edge of astill further alternative disc having a chamfered edge and FIG. 8 is adetail cross-sectional view of an entry noz- 'zle for use in thevibrator shown in FIGS. 1 and 2.

FIGS. 1 and 2 show a vibrator which in practice may be about four inchesin diameter. The vibrator includes a casing comprising two casingmembers 1 and 2 which engage each other in a plane 9 and are heldtogether by four set-screws 3.

Within the casing there is a cavity 4 defined by a concave sphericalsurface 8 and by inwardly projecting lower and upper coaxial conicalsurfaces 5 and 6. The cavity 4 is symmetrical both about the plane 9 andabout the axis of the conical surfaces 5 and 6.

Within the cavity 4 there is a fitted an inertia disc 7 of substantiallythe same diameter as the spherical surface 8. The disc 7 is movable inrotation about its axis and is also tiltable into and out of alignmentwith the plane 9, this tilting being limited by the axially oppositefaces of the disc making line contact with the generators of conicalsurfaces 5 and 6 respectively.

Substantially in the plane 9 there is an inlet 10 for a working fluid.The inlet 10 is shaped to hold a nozzle such as is shown in FIG. 8 andto align the nozzle for directing the working fluid along a pathsubstantially in the plane 9 and to one side of the axis of symmetry ofthe cavity 4. There is also an outlet for the working fluid, such outletbeing comprised of a row of parallel channels 11 distributed along theline of intersection of the conical and spherical surfaces 5 and 8 inthe element 1. That the fluid outlet is a row of apertures eliminatesthe need for any filter means to prevent the ingress of dirt or othercontaminant when the vibrator is not in use.

In the vibrator shown in FIG. I the disc will be maintained in aninclined position relative to the plane 9 by ball-ended rods 14 and 15.These ball-ended rods 14 and 15 engage, with their balLends l6and 17respectively, hemispherical recesses 18 and 19 centrally located in theopposite faces of the disc 7. The recesses 18 and 19 are shown mostclearly in FIG. 4. The rods themselves are received within coaxialconical recesses 12 and 13. in the apices'of the conical surfaces 6 and5. The nozzle shown in FIG. 8 comprises a body 29 having ascrew-threaded portion 28 by which it can be screwed into the inlet 10shown in FIG. 1. Forward of the screwthreaded portion 28 there is aconnector 30 which may be provided with screw threads or be shaped toreceive as a push fit over it a mouthpiece 31. The mouthpiece 31 is ofelastically deformable material such as rubber or a synthetic plasticand comprises a converging passage 32 terminating in an orifice 33. Thesize of the orifice 33 depends on the flow rate of working fluid passingthrough the nozzle so that when the flow rate is increased, the orificewill expand accordingly. By using a nozzle of this kind, a jet ofworking fluid can be created within the cavity 4. It will be understoodhowever, that the nozzle may also have other applications.

The operation of the vibrator will now be described. When a jet ofworking fluid is introduced into the cavity 4 through the mouthpiece 31positioned within the inlet 10, it will impinge on one or other surfaceof the disc 7. In the position of the disc 7 shown in FIG. 1, the jetwill impinge on the lower surface of the disc and will cause theperiphery of the disc to roll upon the conical surfaces 5 and 6 in aclockwise direction (FIG. 2) so that the axis of the disc will perform anutating movement about the axis of symmetry of the cavity 4. It is thisnutating movement of the disc 7 which causes the vibration of thevibrator. Although the disc 7 has been described as rolling on thesurfaces 5 and 6, the movement will actually be a combination of rollingand slid- Alternative forms of disc are shown in FIGS. 3, 5, 6, and 7,the simplest form of disc being shown in FIG. 3. The disc 7 shown inFIG. 3 has no central recesses 18 and 19 and is provided simply withparallel opposite surfaces.

The disc 7 shown in FIG. 5 is provided with ball hearing means 21 bywhich it is mounted on a shaft 20 supported coaxially with the axis ofsymmetry of the cavity 4. The ball bearing means permits the disc 7 tomove as described with particular reference to FIG. 1 and alsomaintainsthe disc accurately centered upon the axis of symmetry of thecavity 4.

FIG. 6 shows an alternative bearing means for the disc 7 comprising acentral ball 23 supported within the cavity 4 on the axis of symmetrythereof. The ball 23 is received within recesses 24 and 25 in the apicesof the conical surfaces 5 and 6 and the disc 7 is provided with anopening 22 within which the ball 23 is received.

It may happen that there is difficulty in starting the vibrator wherethe disc 7 is of the kind shown in FIGS. 3, 5 and 6. This difficulty canarise where the disc is started from an at-rest condition aligned withthe plane 9 or otherwise obstructing the inlet 10. The disc shown inFIG. 7 can overcome this difficulty by having its periphery chamfered at26 to a circular line edge and in association with this the inlet 10 hasa channel 27 extending into the element 2. In the position of the disc 7shown in FIG. 7, working fluid jetted into the cavity 4 through theinlet 10 .will be deflected by the disc 7 both upwardly and downwardly,but in view of the channel 27, more fluid will be deflected upwardlythan downwardly, and this in turn will cause the disc 7 to tilt out ofalignment with the plane 9 and to commence its nutating movement.

It will be appreciated that the description of the present embodimentsof the invention are given for the purpose of illustration only and thatthe invention can be embodied in other forms within the spirit and scopeof the appended claims.

I claim:

1. A vibrator comprising a casing, a cavity within the casing, nutatinginertia disc means in the cavity guided by cooperating surfaces of thecavity, [and] inlet means and outlet means for conducting a workingfluid into and out from the cavity wherein said inlet means ispositioned in a wall of the casing to direct the working fluid into thecavity along a path lying substantially in the plane of symmetry of thenutating movement of said disc means, whereby working fluid directedinto the casing by the inlet means will impinge upon the disc means tocause nutating movement thereof, the inlet means and the outlet meansfurther being arranged to conduct the working fluid exclusively throughstationary parts of said casing, and a supporting element guided 'insaid casing and connected with said disc means on at least one sidethereof.

2. A vibrator as claimed in claim wherein said '56 operating surfacesdefine said cavity and are so shaped that the outer periphery of saiddisc means is in subs satiaLtql iassnsss asstw i. Surfaces- 3. Avibrator as claimed in c laim f wherein said supporting elementcomprises bearing means mounted in said casing.

4. A vibrator as claimed in claim 1 wherein said cooperating surfacesinclude two inwardly projecting conical portions, said conical portionsbeing disposed each on axially opposite sides of said disc means, eachsaid conical portion being a coaxial mirror image of the other and eachsaid conical portion carrying at its apex a respective supportingelement for said disc means, said disc means being tiltable out of saidplane of symmetry to a maximum inclination wherein axially oppositefaces thereof make line contact each with a respective generator of arespective one of said conical portions.

5. A vibrator as claimed in claim 4 wherein each said supporting elementis a ball-ended rod comprising a rod portion carrying a ball at one end,said balls being received each in a respective socket in a respectiveone of said axially opposite faces of said disc means and said rodportions being received each within a respective conical recess in theapex of a respective one of said conical portions, and bearing againstthe inside surface of said conical recess.

6. A vibrator as claimed in claim 4 wherein said disc means includes atits centre a mounting ball having parts thereof exposed on axiallyopposite sides of the disc means, said exposed parts being received incomplementary sockets which comprise the supporting elements in theapices of said conical portions to provide a bearing for the disc means.

7. A vibrator as claimed in claim GWhCfElfl said mounting ball ismovably received at the centre of the disc means.

8. A vibrator claimed in claim 7 wherein the mounting ball is'less thanone tenth of the diameter of the disc means.

9. A vibrator as claimed in claim 4 wherein said supporting elements arethe end parts of a shaft carried by the apices of said conical portions,said shaft passes through the disc means, and carries the disc on ballbearing means.

10. A vibrator as claimed in claim 1 wherein the out let means comprisesa plurality of channels connected in parallel.

11. A vibrator as claimed in claim 1 wherein the axially opposite facesof the disc means are flat.

12. A vibrator as claimed in claim 1 wherein the axially oppositc facesof the disc means are conical and are mirror images one of the other,said disc means being progressively thickened towards its periphery.

13. A vibrator as claimed in claim 1 wherein said casing comprises twoelements which contain mirror symmetrical concavities and said entrymeans is positioned in the region of the parting plane of the two parts.

14. A vibrator as claimed in claim 1 wherein said inlet means includes anozzle the cross-section of which increases with increase in the flowrate of working fluid therethrough. i

15. A vibrator as claimed in claim 14 wherein the working fluid is acompressed gas.

16. A vibrator as claimed in claim 15 wherein the working fluid iscompressed air.

17. A vibrator as claimed in claim 16 wherein said inlet means includesa channel for working fluid leading out of said plane of symmetry to oneside thereof.

18. A vibrator as claimed in claim 14 wherein said nozzle includes amouthpiece of elastically deformable material which is deformable by theworking fluid.

19. A vibrator claimed in claim 1 wherein the periphery of said disc ischamfered to a circular line edge.

1. A vibrator comprising a casing, a cavity within the casing, nutatinginertia disc means in the cavity guided by cooperating surfaces of thecavity, inlet means and outlet means for conducting a working fluid intoand out from the cavity wherein said inlet means is positioned in a wallof the casing to direct the working fluid into the cavity along a pathlying substantially in the plane of symmetry of the nutating movement ofsaid disc means, whereby working fluid directed into the casing by theinlet means will impinge upon the disc means to cause nutating movementthereof, the inlet means and the outlet means further being arranged toconduct the working fluid exclusively through stationary parts of saidcasing, and a supporting element guided in said casing and connectedwith said disc means on at least one side thereof.
 2. A vibrator asclaimed in claim 1 wherein said cooperating surfaces define said cavityand are so shaped that the outer periphery of said disc means is insubstantial rolling engagement with said surfaces.
 3. A vibrator asclaimed in claim 1 wherein said supporting element comprises bearingmeans mounted in said casing.
 4. A vibrator as claimed in claim 1wherein said cooperating surfaces include two inwardly projectingconical portions, said conical portions being disposed each on axiallyopposite sides of said disc means, each said conical portion being acoaxial mirror image of the other and each said conical portion carryingat its apex a respective supporting element for said disc means, saiddisc means being tiltable out of said plane of symmetry to a maximuminclination wherein axially opposite faces thereof make line contacteach with a respective generator of a respective one of said conicalportions.
 5. A vibrator as claimed in claim 4 wherein each saidsupporting element is a ball-eNded rod comprising a rod portion carryinga ball at one end, said balls being received each in a respective socketin a respective one of said axially opposite faces of said disc meansand said rod portions being received each within a respective conicalrecess in the apex of a respective one of said conical portions, andbearing against the inside surface of said conical recess.
 6. A vibratoras claimed in claim 4 wherein said disc means includes at its centre amounting ball having parts thereof exposed on axially opposite sides ofthe disc means, said exposed parts being received in complementarysockets which comprise the supporting elements in the apices of saidconical portions to provide a bearing for the disc means.
 7. A vibratoras claimed in claim 6 wherein said mounting ball is movably received atthe centre of the disc means.
 8. A vibrator as claimed in claim 7wherein the mounting ball is less than one tenth of the diameter of thedisc means.
 9. A vibrator as claimed in claim 4 wherein said supportingelements are the end parts of a shaft carried by the apices of saidconical portions, said shaft passes through the disc means, and carriesthe disc on ball bearing means.
 10. A vibrator as claimed in claim 1wherein the outlet means comprises a plurality of channels connected inparallel.
 11. A vibrator as claimed in claim 1 wherein the axiallyopposite faces of the disc means are flat.
 12. A vibrator as claimed inclaim 1 wherein the axially opposite faces of the disc means are conicaland are mirror images one of the other, said disc means beingprogressively thickened towards its periphery.
 13. A vibrator as claimedin claim 1 wherein said casing comprises two elements which containmirror symmetrical concavities and said entry means is positioned in theregion of the parting plane of the two parts.
 14. A vibrator as claimedin claim 1 wherein said inlet means includes a nozzle the cross-sectionof which increases with increase in the flow rate of working fluidtherethrough.
 15. A vibrator as claimed in claim 14 wherein the workingfluid is a compressed gas.
 16. A vibrator as claimed in claim 15 whereinthe working fluid is compressed air.
 17. A vibrator as claimed in claim16 wherein said inlet means includes a channel for working fluid leadingout of said plane of symmetry to one side thereof.
 18. A vibrator asclaimed in claim 14 wherein said nozzle includes a mouthpiece ofelastically deformable material which is deformable by the workingfluid.
 19. A vibrator as claimed in claim 1 wherein the periphery ofsaid disc is chamfered to a circular line edge.